Accordingly, the CTA Division declared the assessment and the CIR's final demand void and of no effect, and it ordered the cancellation of FAN No. 34-2001 for DST. [14] The CIR's Motion for Reconsideration was denied on June 4, 2019. [15] The CIR elevated the matter to the CTA En Banc , principally arguing that the CTA Division erred in ruling that prescription had set in. [16] On June 21, 2021, the CTA En Banc rendered the assailed Decision [17] denying the CIR's Petition and affirming the CTA Division's ruling. Notably and central to an issue now before the Courtthe CTA En Banc , on its own initiative, addressed an issue that had not been explicitly raised by either party: whether the revenue officers who continued the DST audit and whose findings led to the DST assessment in question were duly authorized by a valid LOA . The CTA En Banc answered this in the negative, holding that the absence of an LOA covering the ROs who issued the PAN, Amended PAN, and FAN rendered the assessment void ab initio . The CTA En Banc cited Section 13 [18] of the NIRC and BIR administrative issuances requiring a separate LOA for any reassigned examination, and it concluded that the failure to issue a new LOA when new officers took over the audit was fatal to the assessment's validity. [19] The CTA En Banc went on to affirm that, in any event, the right to collect had prescribed, as earlier held by the CTA Second Division. [20] The CIR's Motion for Reconsideration was denied on March 18, 2022. [21] Hence, the CIR filed the present Petition. Arguments of the Petitioner The CIR contends that the CTA En Banc acted beyond its authority and violated the CIR's right to due process when it considered and ruled upon the issue of the lack of a proper LOA for the revenue officers who conducted the DST audit, an issue allegedly never raised by the parties in their pleadings or during trial. The CIR argues that granting relief on a ground not raised by respondent or not put in issue during the proceedings is improper and violative of the basic tenets of fair play. [22] The CIR argues that, in any case, the requirement of an LOA for the revenue officers was substantially complied with. It asserts that the original LOA was valid and that the subsequent audit by different examiners was authorized through an LN or internal memoranda. The CIR maintains that the absence of a new LOA did not invalidate the assessment, implying that the LN and the sign-offs by superior officers sufficed to clothe the subsequent examiners with authority to examine respondent's books. [23] The CIR further contends that the five-year prescriptive period to collect the assessed DST did not lapse, because the running of the period was suspended by certain acts attributable to Standard Insurance. In particular, the CIR points to: (1) a Letter, dated January 21, 2005 from Standard Insurance requesting the BIR to hold in abeyance any collection or enforcement of the assessment while the protest was pending